Rotary blower



B.HEMBACH ROTARY BLOWER Jan. 16, 1945.

Filed March 2, 1940 2 Sheets-Sheet l en Q M A tto/'ney IIIIII'."

Jan. 16, 1945. y B, HEMBAQH 2,367,463

ROTARY B'LQWER Filed March 2, 1940 2 Sheets-Sheet 2 Affe/'nes' Patented Jan. 1s, l194s ROTARY BLOWER v Bruno Heimbach, Stuttgart, Germany; vested in the Alien Property Custodian Application March 2, 1940, Serial No. 321,834

In Germany March 18, 1939 4 Claims.. (Cl. 230-141) This invention relates to rotary blowers of the rotary piston type having two oppositely-rotatvable interengaging rotors substantially 4sealed with respect to each other and to the walls of the working cylinder. For best operation under all normal conditions of operation, the end and outer faces of such rotors should have in normal operation as little clearance with the cylinder walls as is possible, but at the same time contact therewith yshould be avoided particularly on account of the high speeds at which such blowers are sometimes driven.

The primary object of this invention ls to provide a rotary blower of this type in which the rotor or rotors may be accurately centered in the working cylinder and maintained during normal operation in free running position therein with minimum clearance. This result is attained in a construction in which normally stationary cylinder heads support the rotor bearings and accurately lit the cylindrical wall of the cylinder. Since these walls should be accurately machined in any event, additional precision is not entailed thereby. In my construction, however, one of these cylinder heads is adjustable axially of the cylindrical wall of the working cylinder, to provide initially upon assembly the proper end clearances for the rotor, by means of a spacing member located between two members rotatable with the rotor in such manner that the spacing member rotates with the rotor free from contact with the adjustable cylinder head, suitable mechanism also being provided for automatically compensating for changes in clearance at the end faces of the rotor or rotors due to temperature variations in the parts under normal conditions of operation of the blower.

Still other objects of the invention will be apparent from the following description taken-in connection with the accompanying drawing illustrating the preferred embodiment. In the drawing, Fig. 1 is a central longltudinalsection, partly in elevation, of the blower; and Fig. 2 is a section on line II-II of Fig. 1.

Within the`blower casing 5, provided with a suction space 6 anda pressure space l, are two oppositely rotating rotors. 8 each having two vanes 9. These vanes rotate with small clearance in the accurately machined cylindrical walls I of the working cylinder 5, 1 d in the grooves Il. To accurately center the 4rotors 8, the frictionless bearings I4 at one end of each shaft and I5, I6 at the other end, are supported in sleeves I'I and I8, respectively, forming integral parts of the cylinder heads I9 and 20 which accurately t within the cylinder wall I0. The sheet metal ring 2I between the inner races of the ball bearings I5, I6 of each rotor shaft displaces them to such an extent with respect to the outer races thereof that axial play is eliminated. On each shaft, between the inner race of bearing I 6 and the collar I3, which is fixed on or is integral with the shaft and which forms with proper packing material a labyrinth packing around its periphery in the opening in the cylinder head 20, is a washer or shim 22 of such chosen thickness that the clearance between each rotor 8 and the cylinder head 20 may be adjusted to a predetermined Small amount. The outer races of the bearings I5, I5 of each rotor shaft are fixed in the sleeve I8 against a shoulder thereof by the exteriorly threaded ring 23, while the nut 24 on the end of the rotor shaft secures the inner races axially on the shaft, the gear 25, keyed on the shaft, together with the washer 26 and ring 21 being interposed. In this way the inner races of the bearings I5, I6 rotate with the rotor shaft, and the Washer 22, which initially adjusts the axial position of the cylinder head 20 in the cylinder I I), rotates with its rotor 8 free fromcontact with its stationary cylinder head and the parts carried by it. By providing the gears 25 with helical teeth, noise is reduced and the angular relation of the two rotors 8 may be adjusted by properly changing the thickness of one of the two washers 26. By means of ring nuts 28, the sleeve I8 is held rigidly in the sleeve 29 of the casing 30 to which is fastened the end cover 3| for enclosing the part as shown. I l

The lower rotor shaft -I2 is longer than the upper shaft and extends through the cover 3|, which carries a bearing with an oil lseal 33 for the drive coupling 35 fastened by a nut on the end of the shaft. The hub of each gear 25 is journaled in a roller bearing 36 mounted'in a bearing member 38 with a flange 39 tted into a recess of the casing 30 accurately coaxial with the sleeve 29. Each bearing 36 formsV a thrust bearing for its shaft and should be accurately positioned coaxially with the other bearings supporting the shaft.

The sleeves I'I supporting. Athe thrust roller.

bearings I4 of the two rotor shafts are accurately fitted into bores of thecasing 'Ill4 and secured thereinlby ring nuts 28, the outer races being fixed by spring rings 34 and the inner races being pressed by nuts 24 against the respective shaft collars 43 forming labyrinth packings, as before, in the openings through the cylinder heads I9. The outer diameter of these collars 43 is some-k Jto be forced by said what larger than the inner diameter of the outer races of bearings Il, so that by'using the customary roller bearings, in which a cage is pro- `vided on the inner race, the rotors 8 may be installed and removed with the casing 30 without -5 removing the casing 40. Furthermore, this arrangement -permits the transposition of the casing members 30 and 40 with their associated f parts, so as to change the drive coupling 35 to Vdetermining the `axial adjustment ofthe rotor with respect to said disk, adiustablemea'ns on the rotor shaft opposing said collar-.in eiective engagement with the inner race of the bearing the other end if desired. Furthermore, by maklo Thus the blower/may be adapted to different driving conditions, which is especially important in its association with internal combustion engines. This nexibility results from the fact that by omitting `the usual methods of construction, requiring for locking'the rotor in the desired axial position of clearance adjustment relative tothe disk afforded by the presenceof the said spacer with respect to the adjacent end ofthe rotor whereby the end of the rotor has the desired clearance with respect to said disk and said rotor including spring means operating in an axial direction `\between a part of the rotor and the corresponding rotor shaft for automatically maintaining the' clearance by compensatingv for axial expansion and contraction of the rotor due to changes in temperature in the blower.

2. In a rotary blower of the rotary piston type having two oppositely rotatableA interengaging dowel pins among other things, the accurately machined cylindrical walls I0 s erve for centering the sleeves I1 and I8, and the cylinder heads I9 and 20 are held at a proper distance axially in the casing members 3|! and 40. At the same time,

be adjusted so accurately that frictional'contact with the cylinder heads is avoided and theI loss occurring there in operation of the'blower is a minimum. Preferably the adjustment of these the clearance-of the end faces of the rotors 8 may 20 clearances is eiected at the normal operating 'temperature of the blower.

Inasmuch as the rotor shafts are of metal of nigh-tensile strength as steer whne the rotors s and their vanes 9 are preferably of metal expanding linearly at a greater rate upon heating, provision is made to automatically compensate therefor by the following construction.` The col lar 43 of the upper rotor is provided with a hub 42 which is inserted in the bored end of the rotor.

the shoulder 45 of the hub and at the other end against the nut 4B on a tensioning bolt 41 screwed into the rotor shaft. In the case of the lower rotor, the shaft I2 extends through the rotor and* has a shoulder 5I against which the hub 52 of 45 rotors including rotor shafts on which the rotors can slide axially, a rotor chamber comprising a part-cylindrical wall and cylinder heads, one of said cylinder heads comprising a member xed with respect to the chamber and formed with-a sleeve having a bore coaxial with said part- 50 cylindrical wall, said cylinder head further coin-` prising a disk fitting the part-cylindrical wall of the chamber, said disk being .formed with a second or inner sleeve slidably fitting the bore of the first or outer sleeve, the bore of the inner sleeve opening through said diskand being 'ooncentric with respect to said part-cylindrical wall, an anti-friction bearing on the shaft of one of therotors within said' inner sleeve, said bearing having its inner race fixed on the Vrotor shaft and its outer race fixed within said inner sleeve, acollar on the rotor shaft, a spacer on the rotor shaft between said collar and the inner race, and rotatable therewith out of contact with said inner sleeve, the thickness of the spacer substantially rotors including rotor shafts on which the rotors can slide axially; a blower housingy comprising a rotor chamber including a part-cylindrical por tio'n for each rotor and cylinder heads on opposite ends of the rotor chamber, one of said cylinder heads comprising a. member fixed to the housling and formed with two sleeves' through which a portion of the rotorl'shafts Dass, the'cylinder head further comprising two disks each closely fitting in one of said part'cylindrical portions, each disk being formed with a second or inner sleeve coaxial with the corresponding part'cylindrical portion and extending axially through the corresponding one of the first mentioned or outer -sleeves and slidably fitting the bore of the outer Y outer sleeves, a collar on each rotor shaft atone The strong spring 44" reacts at one end against 4o spring 5I against the col- 50 `with the inner races of the bearings for locking the rotors in the desired axial positions of clear- "ance adjustment relative to the said disks afforded 'by the presence of the said; spacers with respect to the adjacent ends of the rotors, said rotors including spring means operating in an axial direction between parts of the rotors and the rotor sh'afts for automatically maintaining the clearance by compensating for axial expansion and contraction of the rotors due to changes in temperature in the blower.

3. In a rotary blower of the rotary piston type,

at least one rotor comprising a shaft and a rotor body which have diierent linear contraction and expansion resulting from temperature changes,

vthe rotor body being slidable along the shaft, a

rotor chamber within which the rotor turnswith one end of the rotor in close clearance with re' spect to at least one endrof the chamber and,

with said shaft fixed against axial displacement in the chamber, and spring means acting between said rotor body and the shaft for moving said rotor body along said'shaft in directions toward and away from the said one end of the chamber to automatically maintain the said clearance during temperature changes within the blower.

4. In a rotary blower of the rotary piston type having two oppiiely rotatable interengaging rotors. a rotor chamber comprisingtwo cylinferent linear contractions and expansions responsive to temperature changes in the blower, and spring means operating between the shaft and the rotor body for automatically moving the rotor body in axial directions to maintain the said clearance during temperature changes in the blower.

BRUNO HEIIVIBACH. 

